1. Field of the Invention
The present invention relates to a display device such as a head-mounted display (HMD) and display device for projectors of the laser scanning type.
2. Description of the Related Art
Heretofore, in liquid crystal display devices such as head-mounted displays, background projection type projectors and the like, so-called multiple panel type display devices have been realized which use a plurality of superposed liquid crystal panels to display wide area or high resolution images. Such display devices, for example, divide an original image vertically and horizontally among a plurality of liquid crystal panels, and by means of and optical system which receives the light of each area projects the image of each area on a screen with consideration given to the projection distance.
In this instance, resolution can be maintained while realizing a display of a wide area if the number of pixels of the screen used as a reference is used directly in plurality grouping. Furthermore, high resolution can be attained using the same screen size if the screen used as reference is divided and the number of pixels of each screen after division is set at the same number of pixels as the original reference screen. More simply, CRT displays may be arranged in multiple grouping to achieve wide area display. This arrangement is typically called "multivision."
Well understood disadvantages arise in the aforesaid multiple panel type liquid crystal display, however, inasmuch as the borders of each screen are visible and overlap so as to produce a so-called black matrix over the entire screen. As a result, conventional methods must invariably use discrete light sources for each screen, and since projection of the image is accomplished by optical units which receive the light of each area, attempting to eliminate the borders around each screen produces blurring which prevents accurate overlapping of adjacent areas.
Magnification and screen size vary due to slight differences of the optical path of each optical unit. Furthermore, gaps open between the various screens due to interference of adjacent elements of the optical units, and mechanical errors prevent overlapping. When using the aforesaid multivision type CRT display, a frame is clearly apparent on the periphery of each Braun tube from the original. Extremely complex mechanical elements are required to achieve tight overlapping of the areas, with the result that errors cannot be eliminated.